prestashop cron method

mymodule.php

	/* Run cron tasks */
	public function hookActionCronJob()
	{
		return $this->cronTask();
	}
	/* Return cron job execution frequency */
	public function getCronFrequency()
	{
		return array(
			'hour' => -1,
			'day' => -1,
			'month' => -1,
			'day_of_week' => -1
		);
	}